The invention relates generally to control of heating, ventilation, and air conditioning (HVAC) systems. More particularly, the invention relates to a system for detecting airborne contaminants and preventing influx of such contaminants into an enclosed space, such as a vehicle passenger compartment, via a HVAC system.
U.S. Pat. No. 6,206,775 (Lemaitre et al., “the '775 patent”) discloses a motor vehicle heating or air conditioning apparatus including a sensor for detecting a pollutant such as carbon monoxide. Upon detection of a pollutant in the air supplied to the passenger compartment, position of an air intake flap is controlled to modulate flow of exterior air into the passenger compartment. The '775 patent discloses the sensor being adapted to identify relative concentrations of specific pollutants, such as carbon monoxide, using a comparator suitable for comparing a signal associated with a measured pollutant concentration with a reference signal associated with a threshold concentration, below which a level of the pollutant is acceptable (see column 3, line 53 to column 4, line 13). The '775 patent thus discloses a system including a sensor which is capable of identifying a limited set of one or more pre-defined pollutants.
U.S. Pat. No. 6,495,892 (Goodman et al., “the '892 patent”) discloses a system for detecting and identifying analytes in a fluid. In particular, the '892 patent discloses a sensor array formed on an integrated circuit capable of generating an electrical signal which is a “fingerprint” of a given analyte. Pattern recognition processing may be used to identify the analytes on the basis of the “fingerprint” patterns (see column 9, lines 28-43). The '892 patent discloses that the sensor array may be formed from a plurality of sensors formed from conducting polymers the electrical properties of which change when the polymers are exposed to a given analyte, The '892 patent discloses a sensor array which is pre-programmed with a finite set of fingerprint patterns associated with a finite set of pre-defined analytes.
U.S. Pat. No. 5,571,401 (Lewis et al.) discloses a sensor array, of a type similar to that disclosed by the '892 patent, which is capable of distinguishing between first and second concentrations of a given chemical analyte based on measured resistance differences across chemically sensitive resistors (see the Abstract).
A need exists for an apparatus and method of detection and avoidance of airborne contaminants, the operation of which is not limited to a set of pre-defined contaminants.